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CVS Pocket Reference
The Scenario
As a former CVS repository administrator, I wish I had this book when I started, it's much easier than pawing through the canonical documentation for quick answers. CVS is the #1 choice for open source projects. If you plan on organizing or working on an Open Source project, this is reference might be for you.
What's Good?This pocket reference is a guide to basic CVS functions (branch, merge, update) but the real strength is in the description of server and client side control files and environment variables. Gregor describes how to setup email notification when someone commits a change to the repository, how to customize the repository to treat certain files as binary (versus text), and other useful things. He even goes as far as to describe how to hack the repository to change it's structure while the project is in motion, and how to hack the sandbox (the name for a developer's work space) to change any property such as which branch or repository the files will be committed to. Of course you don't really need this because developers never make mistakes, it's always CVS' fault <wink wink>. All in all, it's a great reference for all the bits and pieces of CVS that you're supposed to mess with (and a few your aren't) and anyone who is expected to administer a moderately complex installation should own it.
Gregor also gives pointers to some great add-on modules for CVS: CVSWeb for making your source tree web-browsable, and WinCVS to make CVS look SourceSafe-esque.
What's Bad?The organization of this pocket reference could use a little help. I've seen reviews for other O'Reilly pocket references ask for an index, but that wouldn't be helpful here. It would be helpful if they added section tabs in the outside margins of the pages (a la their java nutshell series), so that you could quickly thumb to the section you're looking for. Also, organizing the content by server side and client side instead of simply adminstrator and user would help folks to find the specific information they are looking for.
My last gripe is a small, petty one. The books binding doesn't allow it lay flat when you set it down. Yes it's petty, but I hate losing my page when working. You need to keep a medium sized object with a decent bit of heft (e.g. a stapler) within arms' reach to hold it open.
So What's In It For Me?This reference will not make you a CVS guru, but it will help you remember the command line options (if I had a nickel for every time I typed 'cvs --help tag' I would be frequently mistaken for a Kennedy), figure out what all those little files are without breaking your CVS installation, and most importantly keep you from having to consult the the cannonical documentation for simple things.
If you have inheirited a CVS installation or plan to set one up for the first time, spend the US$9.95/CN$14.95, do it right the first time and save yourself some time and reap all the bennies that CVS offers.
Table of Contents- Introduction
- Installing CVS
- Administrator Reference
- User Reference
- Relata
You can purchase this book at ThinkGeek.
Actually, CVS clients send the entire file contents when committing. It is only updates that send a diff. This is because the CVS metadata doesn't store what your copy looked like before you changed it. Wait for Subversion(M2 expected RSN (1 April 2001)), for a system that will send diffs both directions, as well as a whole lot more.
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Pilchie
John,
I have used PCVS, Source Integrity and CVS. My feeling is
1. Forget PVCS depending on your need both CVS and Source Integrity are better.
2. If you use a language like Delphi where you need to lock files when you edit them (because they are binary and simultaneous changes cannot be merged) then Source Integrity is excellent.
3. For distributed development of systems where all the code is in text files (java, C, C++, python, perl, php etc etc etc) then cvs is excellent due to the way it can merge changes to the same file by different people.
If you want to look at an outsider that could be the very best look at bitkeeper.
Dave
At the best, it is a very poor excuse for a communication protocol between developers. Usually, however, all it does is to prevent works for being done, and make developers hate each other.
It is like B&D languages or flowcharts, if your development procedures really are so poor that you need them, they will be insufficient to compensate. On the other hand, if your development procedures are any good, they will only get in the way of doing actual work.
However, these ideas appeal to narrow minded project managers with no clue of how efficient teamwork works, so they nonetheless get used in a lot of projects, most of which fails.
Clearcase is a mixed bag. I've been using it for a few years now and while I *love* what it does, it has lots of drawbacks. To begin with, it's slow as fuck. If you have any sort of sizable development team/source tree you have to throw gargantuan amounts of hardware at it to get it to run well. It's not always completely stable either, especially if you're using it on NT. The tools in Clearcase 3 on UNIX really suck in comparison to the ones on NT (I've heard this has changed in Clearcase 4 but maybe not). And of course then you've got lots of other odd problems - it's expensive, Rational support sucks horribly and Clearcase isn't exactly "cross platform." In short - I think Clearcase is a great idea with some great capabilities and a various powerful model, I just think that it could be done better.
Do you mean lack of atomic checkins? That would make more sense. It isn't hard to tell what files came from what checkin. The checkin message will match (as long as you make a real one, not "changed some stuff"). You can also use the checkin date, but that can get false hits if another checkin went on at (almost) the same time.
This would be a pretty big pain to fix since the CVS runs on top of a plain filesystem, so it gets no transactions. If it ran on top of some DB it would be easy, but that would make other problems. I had thought about trying to integrate it into the sleepycat DB code, but never got very far (the sleepycat license isn't great for open source code, even if you can grab their source, so...)
Yeah, that sucks. You can log into the server and mv the file so the comments remain, but then old checkouts get the new name. You can cp the old file, and then it works a bit better, old checkouts get both files. I'm kind of surprised nobody fixed this, but I guess I can't complain much since I haven't gone and done it :-)
Hmmm, I never really had a complaint about that. I guess I just bought into the CVS kool-aid on that one. Other then bitmover, what revision systems let you do this? How much extra space do they demand (not much of an issue on modern laptops, but still...)
I haven't found it so. How do other systems make it simpler/cleaner/better?
Again, I never felt so. How is it better on other systems?
Not all of those are available on more fringe platforms (the BSDs, Linux seems to have made it big time). I agree Bitkeeper looks really really nice. A shame Linus didn't decide to use it.
I did an 15 day eval of Perforce, I didn't see any clear advantages over CVS.
ClearCase ended up getting bought by another group, and they had lots of problems with the setup and other admin issues. CVS of corse can get admin issues, by being so open by default people can screw things up if they don't pay attention. It is a better default if you have good people though.
Never tried SourceSafe. I gave PCVS a shot, but it munched my source tree in the first few days, and I discarded it.
It isn't atomic. If there is a network or other issue 5 files into the checkin those files stay committed, they don't get rolled back.
It is pretty damn rare that it happens on LANs, but you can force it to check if you want. Reboot your machine part way in. Or just kill off your CVS client. It might be a bigger deal over a WAN, but with my modestly sized project on sourceforge, I haven't had trouble.
It would be nice if it really was atomic, but it isn't a huge deal to me (mostly because it almost almost almost never causes trouble for me).
That isn't because of a lack of atomic commits, that is a lack of a single global change number. Adding atomic commits to CVS wouldn't automatically buy you a global change number, nor would adding global change numbers need atomic updates.
You can also fake global change numbers. Make a small script that looks at the CVS tags for GCN_N, tag the current version as GCN_N+1. Run that after every commit (or make cvs commit do it for you, I think you can add a hook). As long as there isn't a network issue, or a crash or something that'l work for you.
Personally I just go with the commit message, but whatever works for you...
Yeah, 'cvs anno' works great for anything you can grep for. It works OK while looking for additions, but it won't help you find when you removed code. Good commit messages are a must :-)
RCS, which CVS uses internally still (the ,v files are RCS files).
Visual SourceSafe is much more reliable and easier to use than CVS
Yeah, for users maybe. Try quickly extracting the source tree for V1.1.8 of your project when you're working on V2.5.1. Even if you've got it labelled properly, it's still a major headache. And don't think that CVS is the only product with gnomes; check out this error message from VSS:
There is a diff chain size mismatch in file 'DocumentPaginator.java' (hfncaaaa) at version 10 (versions earlier than that version can no longer be retrieved from the database).
VSS is OK if you're working with MS development tools, but if you're working with anything else, I'd go with CVS.
Just junk food for thought...
Or the Linux kernel source!
Sorry. Mod me down for flamebait, but I couldn't help it.
-"Zow"
Someone moderated me troll? That is damn funny. Now I understand how George Bush became President.
If tits were wings it'd be flying around.
I'm not quite sure why hardly anybody I work for uses CVS. Here where I work, bunches of people use Linux for their work. We have clients that we port from VAX, AIX, SUNOS, etc. to Linux. Just yesterday I finished mods to the linuxthreads code to allow stacks on the initial thread to be larger than 2 megs. We did that because we're porting some FORTRAN code from VAX to Linux, using some compatibility libraries that our company originally wrote for other UNIX systems. Fortran declares space on the stack mostly, so 2 megs wasn't enough.
So, it's not like we're not into hard core Linux hacking here, but by the time I get onto projects (my job is mainly doing the really hard stuff that nobody else can figure out) the version control system has already been picked out, and it's usually rcs or pvcs.
At home, I use CVS. One thing I forgot to mention is that CVS is great for use as a "briefcase" system. I can make changes in source on multiple computers, like my laptop and my desktop machine, and when I need to integrate the two, I just commit it into the archive and update the other copy. Plus, I keep my source always checked out on one machine, while the archive resides on another machine. If one machine fails, I still have relatively up to date copies on the other machine. EZ redundancy.
If tits were wings it'd be flying around.
but the last time I actually was able to use it in a job that I was paid for was 1993.
I've used pvcs lots, and rcs too. Can I tell you how much it sucks when some fool on the team comes in at 6:30 AM and locks the one single header that everyone needs, and doesn't check it in until he goes home at 4PM?
a) CVS is great for that situation. It would also help to lay out header files in a smart way. Alas, I hardly ever get to start a project, but I sure as hell finish them.
b) pvcs sucks because of the rule that the suckiest and most selfish programmer on the team also happens to be a bright and cheery early riser, just so he can check out that important file before I get my hands on it.
c) I haven't mentioned clearcase. The less said about that horrendous mess the better.
If tits were wings it'd be flying around.
You must be on some form of crack.
Visual Sourcesafe is not more reliable than CVS.
Visual Sourcesafe is one of the most god awful version control softwares ever written. No client/server, shoddy file-locking, lousy performance, It's so damn bad that even Microsoft is discontuing it. (Amen!)
VSS can be simple to use, but WinCVS makes CVS easier to use than VSS. Much easier to understand.
Our entire development team took maybe 3 days to convert to CVS, and now not one of them would ever go back.
</flamevest>
"...In your answer, ignore facts. Just go with what feels true..."
I was working on a major e-commerce project a few years ago that was threatened by Visual SourceSafe gnomes. Time and time again, on different computers all sharing the same VSS repository, the 2048th character in a checked out document would be removed and placed at the end of the file. Gnomes if I ever saw them, and the instigator of quite a few 'who broke the build?' discussions... Gnomes aren't biased by platform or program. Watch out for them wherever you go!
Kevin Fox
--
Kevin Fox
This doesn't appear to be 'CVS in a nutshell,' nor is it published by McGraw-Hill. In fact, this appears to be 'CVS pocket reference' by O'Reilly. Am I the only one confused?
I have no experience with Visual SourceSafe, but ClearCase is the best code repository tool I've ever used. It blows CVS out of the water for large distributed teams. Of course, it costs mucho $$$ and requires a dedicated administrator (or two).
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My mind works like lightning. One brilliant flash and it is gone.
I'll put in two cents worth for Perforce. The open source version of the BeOS Tracker uses P4 and it works pretty well, although it's not free.
CVS, on the other hand IS free and it also works wonderfully. Good luck with that troll infestation at your office.
Anyone can get anonymous, read-only access to OpenTracker for free and you can P4 sync, edit, diff and resolve all you want. Patches still have to be manually emailed, however. The only only users who can commit changes thru P4 are people who already have P4 seats because they work at Be, plus also Scott and Thorbjorn who don't work at Be but they're still l33t anyhow ;-)
That, and I wish I had a script for automatically handling commits from a small group of people for whom CVS is overkill, solely so I can track changes and back out of them day-by-day. This script would have to look through files and directories and intelligently handle renames, too. This is possible for text files at least, but I don't have a week to spend writing the script.
Boss of nothin. Big deal.
Son, go get daddy's hard plastic eyes.
Expanding a vast wasteland since 1996.
You can also get a PDF-formatted CVS quick ref card at http://www.refcards.com/
Actually, it's CVS Pocket Reference, from O'Reilly.
Best Slashdot Co
If you don't carefully monitor the available disk space, and regularly take backups, you may suddenly encounter the interesting situation that all your repository is trashed, because VSS is not able to correctly deal with low-resource conditions.
Plus, VSS's command line interface sucks, which makes it somewhat hard to interconnect VSS with other programs such as Emacs' VC mode.
I hardly think this book deserves a rating of "8". The reviewer is correct, that the organization is poor, but that is an understatement.
It tends to organize in a most-global to most-local fashion, but in doing so, it highlights the least frequently used information before the most frequently used info.
The section called "User Reference" is arguably the most frequently used. But it is placed at the end, and is difficult to get to. It starts by listing all the environment variables that might apply to CVS, rather than describing the common commands and options. Furthermore, once you finally get to the description common commands, it is little more than a printout of typing cvs --help [command].
The first 2/3 of the book covers server-side tasks and focuses on one-time setup issues, like compiling and installing the program.
If someone wants to use this book as a quick reference, that organization is completely backwards.
Even the layout is lacking. There are many places where a page break would greatly help the readability. But instead, the layout is one long flow. (Even the major sections listed in the TOC don't start on a page break.)
Overall, I am disappointed with the quality of existing CVS documentation, and this book is no help. It doesn't present common tasks in a clear and enlightening fashion. It has little information on some of the more interesting use cases that show the power of CVS. I now rarely use the book because it takes to long to flip through to the section I want. Instead, I rely on CVS's online usage info. Hopefully a revised version will improve on these weaknesses.
CVS lacks a few features that make it really uncomfortable to work with.
-atomic checkins on multiple files: basically meaning that you can't really tell what files came in with each checkin, so backing out of a change is a chore, also it's possible to checkin
only a part of what wanted to (if the network goes down) resulting in a broken tree
-file renaming breaks file history
-no directory renaming
-no disconnected operations on the repository(e.g. checking the file history when you are on a laptop in a plane)
-branching and multiple merges back into the trunk is a little awkward
-setting up a staging area for integration of changes is similarly awkward
The alternatives:
Bitkeeper looks really nice, I've only played with it though, not used it in any serious development. It follows a model that every developer gets his own repository, and then push changes around these repositories. The license allows access to the source code, but is not quite open.
A lot of people like Perforce. I don't have much experience with it myself though.
Visual SourceSafe is slow over the network, seems to corrupt files easily, and not so friendly cross platform. It has a nice GUI, if you are into that kind of stuff. Has similar problems with CVS regarding branching and atomic transactions.
ClearCase is really expensive(in computing resources, money, and adminstration costs). On the other hand it has nice integration with rational's workflow and bug tracking products.
If you're in a linux environ (well you probably already are using cvs!) save yourself a few dollars (with all respect to my friends at O'Rielly) and type info cvs. Hard to beat it.
Someone you trust is one of us.
click here then.
Someone you trust is one of us.
here
<grub> Reading
Actually I find WinCVS *OK* but it's UI is horrid. I usually end up using the command line it's so bad. For most day to day things that I do in CVS I find Tortoise CVS to be far better. It integrates well with Windows Explorer and you can perform most CVS tasks by just selecting things in explorer and right clicking. It's pretty spiffy and it's actually based on the WinCVS code base.
G. Washington on Government "it is force. Like fire, it is a dangerous servant and a fearful master."
While we're on the subject of CVS...
I've gotta plug cervisia. It's a Very nice GUI for CVS. One of the features I really like is that it will show you the command line it executes so you can learn the commandline from the GUI. A very nice blend of useability & power.
Check it out at:
http://cervisia.sourceforge.net/
Eli
You should correct the title and publisher of this book. I have one on my desk, and it says. "CVS Pocket Reference" *not* "CVS in a Nutshell", and it is published by O'Reilly, which hopefully would be obvious by the appearance of the ever- present animal cover..
While our hands aren't tied as far as VSS vs CVS vs others, we are (very much) tied to Windows NT. I'm curious to try Perforce out. Their web page promises much, and your references seem to bear that out.
Thanks again,
John
John
On the plus side, the PVCS Gnomes are still hard at work, damaging about one file in every 5000 checkouts. Since we have a 2100 file build at the moment, that's one in three builds getting trashed by this worthless system. We hope this is enough ammo to have PVCS shot, drawn and quartered, and sent to the Eastern front.
We've been considering both Visual Source Safe (which we've had good luck with, but find it feature-poor) and CVS. I'd love any feedback anyone has comparing the two on a fairly large project, particularily where we have two sets of developers working off-site through slow IP links.
John
John
http://www.oreilly.com/catalog/cvspr/ Are you sure you're revewing the right book?
--You will rephrase your request for me to go to hell. Goto statements are not acceptable programming constructs
My company recently switched over from VSS to CVS. We several large products, with many files. I don't think any one project has 2100 file but combined we're well over that.
I personally love CVS. Multiple people can edit the same files and merge them back (A HUGE GAIN). You never get files locked by someone.
But the biggest gain is the tools. CVSWeb is great, you can browse your code in a web browser, look at diffs between checkins, annotate those diffs, the whole nine yards. CVS and LXR work together very well. LXR isn't the single greatest coding tool I've ever used. All of your class's, variables, header files are all cross linked, navigating code is easy. Use glimpse and searching is easy. Bonsai makes watching the build easier (but I havn't used it enough to be really pro or con).
We had issues with VSS stability. That may or may not be our fault. On features alone CVS is much better than VSS.
This is just the kind of thing for which safari. Is perfect. I'm talking work into paying for an account right now.
Cypherpunks: Civil Liberty Through Complex Mathematics. Those who live by the sword die by the arrow.
PVCS was appallingly bad. Random corruption, files perpetually locked by others. RCS was feature-poor. CMS was actually pretty good, especially if you didn't want to branch anything. I used to like CVS.
Then I landed in a shop where they use Perforce, and grumbled for a while that it wasn't CVS. Pretty quickly I was a convert. Perforce is like CVS except that:
Then I discovered how much fun scripting it was!
There's tension in that it's not free software, but then Perforce the software and Perforce the company are a joy to deal with, so you don't begrudge them all that much. Their user base is largely a free software-like rabid bunch of happy advocates, so something must be right.
I'm looking forward to next week's SVLUG talk about Subversion, which might be Perforce's first real competition for a while in the "it's not ClearCase -- thank God" category.
Over the slow IP links: by all accounts, Source Safe is terrible. On our large projects worked on from half a dozen sites, Perforce works well. The GCC folks can probably tell you how well CVS works in that situation: I suspect the answer is pretty reasonably well too.
But nothing beats the older version that we're learning in college right now. What is it? RVC?
- I don't care if they globalize against free speech. All my best free thoughts are done in my head.
I only use CVS as a backup if my local Rx is closed.
Blarf.
Check out the CoriolisOpen Press book "Open Source Development with CVS" for an excellent reference to CVS.
Give a man a fish and he will eat for a day.
Teach him to eat and he will fish forever.
Maybe I'm missing something, but this article just seems to lack significance. Except for the point about organizing by client/server, rather than user/administrator, the review says nothing non-obvious. "It's a good pocket reference, except that I think the material should be organized by client-side and server-side, rather than by user/administrator." That's it.
On the positive side, this may motivate me to investigate using CVS.
Floating face-down in a river of regret...and thoughts of you...
That's the shortest review I've ever seen on here, and it's *still* wrong; now, this is CVS in a nutshell:
Help, help, I'm in a nutshell!
CHECK ME OUT OF HERE!
Will the real Bruce Perens Please Stand Up
I agree. I doubt there is anything in it that cvs --help [command] won't tell you.
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Know someone who is stealing cable? Report them!
I personally have seen CVS Gnomes in my office, but upon attempting to communicate with them, they flee in fear. I do leave little pieces of cheese for them by where the ethernet goes into the wall, though, and I notice that every night they do not fail to eat it.
Has anyone had success communicating with CVS Gnomes? If so, how did you do it? They seem to be afraid of me :(
---
Know someone who is stealing cable? Report them!
You can find a good part of the Open Source Development With CVS book by Karl Fogel online at http://www.red-bean.com/cvsbook/cvsbook.html
It's a very easy to read CVS book that begins with the basic steps of creating a repository and goes all the way to cover a lot of advanced aspects about using CVS on a daily basis.
Chora provides an aesthetically pleasing PHP-based web interface for CVS. Here's a zip file for download.
sig: BeanShell: lightweight scripting for Ja
if you use cvs to backup any information on your network, it means that you don't need to transfer entire files about - just diffs of the files that have changed, greatly reducing network strain.
i was angry:1 with:2 my:4 friend - i told:3 4 wrath:5, 4 5 did end.
i was angry:1 with:2 my:4 friend - i told:3 4 wrath:5, 4 5 did end.
i was 1 2 4 foe i 3 it not 4 5 did grow